Means for automatically cutting off the feed motion of machine tools



N. J. OLSSON. v v MEANS FOR AUTOMATICALLY CUTTING OFF THE FEED MOTION OF MACHINE TOOLS.

' APPLICATION HLEQ AUG-23. 1919.

1,421 ,5 44, v Patented July 4, 1922.

SVENSKA KULLhGERFIlBR-IKEN, 0F GOTTENBDEG,

MEANS FOR AUTOMATICALLY CUTTING OFF FJW'EDEN, A. CORPORA- TI-IE FEED MOTION OF MACHINE TOOLS.

Original application filed August 1, 1918, Serial No. 247,784.

T 0 all whom it may concern.

Be it known that 1, time J osnr OLssoN, a sub]ect of the King of Sweden, residing at Gottenborg, in the Kingdom of Sweden, have invented certain new and useful Improved Means for Automatically Cutting Oif the Feed Motion of Machine Tools, of which the following is a specification.

This invention relates to automatically operating devices for cutting off the feed motion of grinding machines and other machine tools when the work reaches its desired ultimate diameter, and more particularly to such devices of that class as are de scribed in my co-pending application for patent Serial No. 241,392, filed June 22, 1918, in which a pivotally mounted lever bears against the work or against a movable member bearing in turn against the work, said lever being so arranged and so formed at its contact point that it will be locked by said engagement until the desired diameter of the work is reached, whereupon the lever will by means of a spring, a weight or the like be brought out of engagement with the work and caused to initiate the cutting off of the feed motion. 7

In order to render the device more reliable and more durable, that is to render it inde pendent to a larger extent of the wear at the contact point of the lever, the end of the lever bearing against the work or against the intermediate member is formed, according to one embodiment of the invention set forth in my above said application, as an arc the centre of which coincides with the axis of the lever. 'By so forming the lever the effect of the wear is almost completely eliminated as the are proper contacts with the work or with the intermediate member at the releasing moment only.

According to this invention a still more reliable and durable device of the above said kind is obtained by forming the lever of two 7 separate parts adjustably connected with each other, the part bearing against the work or against the intermediate member having the shape of a toothed disk, the top surfaces of the various teeth of the disk forming parts of cylindrical surfaces having different radii but a common centre coinciding with the axis of the lever.

This construction permits the use of a single disk for controlling the cutting off Specification of Letters Patent.

example of a feed 'vri tii Patented July 1, t me Divided and. this application filed August Serial No. 319,42.

action for work pieces having different ameters withoutany adjustment of the de vice with relation to that part of the grindmg machine carrying the device.

In the accompanying drawing Fig. l is a side elevation of a device constructed according to this invention shown partly in section.

Fig. 2 is a diagrammatic view showing an F stop means controllable according to the present invention.

Referring to the drawing, the numeral 1 indicates a casing enclosing a lever 3, 4, carried by the pivotally mounted shaft 2, one arm 4 of said lever being rigidly attached to said shaft and being formed at its outer end as a hammer. Mounted below said hammer is a contact spring 6 adapted to co-operate 1 an underlying contact piece 7. The arm 4- is controlled by a spring 8 tending to keep the lever in the position in which the hammer of the arm 4 keeps the spring 6 in contact with the fixed contact 7. The hammer of the arm 4t is formed with a hookshaped portion 9 adapted, when the arm 4 is lifted up, to be engaged by a pawl 10 when it is required to keep the lever out of operative position, as is shown by dotted lines, the pawl 10 being withdrawn manually to release the lever when the device is ready to operate.

The arm 3 of the lever 3, 4, consists of a disk so connected to the shaft 2, as by a nut 24. screwing on the shaft, that the disk 3 may, after the said nut has been released,

be turned about the shaft 2 to bring a clifferent tooth into operative position, after which the nut is tightened to hold the disk fast on the shaft.

The disk 3 is provided with six recesses 23 forming a corresponding number of teeth 27, each having an edge 25. The circumferential or top surfaces of the teeth 27 form part of cylindrical surfaces having different radii but a common centre coinciding with the centre of the shaft 2.

The contacts 6 and 7 are intended to be included in the circuit of an apparatus for cutting oif the feed motion of the grinding machine or other machine tool in connection with which the device is intended to be used. Said apparatus may be of any con venient or know type and will not be described as it does not form any part of this invention. The distance between the contacts 6 and 7 should "be so chosen that the tension existing in the said circuit will not be high enough to cause the formation of sparks between the contacts when the spring 6 isin its normal position.

The casing 1 is adjustably mounted upon a .suitable base 11 which may form part of a grinding machine or other machine tool, as the case may be, and which may be displaced in the longitudinal direction of the lever 3, i by means of a screw 12.

The apparatus shown is especially adapted for use in combination with rindin machines for external grinding operations.

When the apparatus is to be used, the lever 3, 4 is first locked by means of the pawl 10 in the position shown by dotted lines whereupon the casing l is so adjusted by means of the screw 12 that the edge 25 of the tooth 27 of the disk 3 to be used will barely clear the work when the latter is reduced to the intended size. Then by withdrawing manually the pawl 10 the lever 9 is released, and the said tooth 27 will be brought in contact with the circumference of the work 26 beneath the horizontal diameter thereof. The work 26 should be rotated in the direction of the arrow so as not to tend to press the disk 3 upward. So

" under the action of the spring 8, which swings the released lever 3, 4- so as to cause it to bring about the closing of the contacts 6 and 7 thus closing the circuit controlling the cutting off of the feed motion of the grinding machine, and so stopping the feed.

In the apparatus above described there is no tendency for premature circuit closing in as much as thelever 3, 4 is completely out of engagement with the contact spring 6 before the said edge 25 has passed the central position. The normally existing distance between the contacts 6 and 7 which is large enough to prevent arcing will thus -be constant until the moment at which the closingis to take place.

' An illustration of one means by which the feed motion may be cut off is shown in Fig. 5, the wires m forming part of an electric circuit making connection with the contacts 6, 7, respectively, and including the winding of an electro-magnet 15, which when energized attracts its armature,.so that thelever- 16 thereof strikes the tail of a gravity or spring pawl .17 carried by a vibrating arm 18, and lifts the nose of this pawl out of the teeth of the feed ratchet 19, thus stopping the. feed. So far as concerns the present invention, any other known means of stopping the grinding operation may be used.

With the teeth 27 of difierent radial projection it is possible by means of a single disk 3 to control the cutting off action for different diameters of the work without any adjustment of the device with relation to that part of the grinding machine carrying the device. The present application is a division of application, filed August 1, 1918, Serial No.

247,784, which has been patented under date of January 20, 1 920, No; 1,328,337.

hat I claim is 1* 1.. The combination in an apparatus for.

cutting off the feed motion of a machine tool when the workhas reached its predetermined size, of controlling means therefor, and a trip lever adapted to co-operate with said-means, comprising an actuating arm and a work-engaging disc having teeth of different radial length, said disc angularly adjustable relatively to said arm to bring either of said teeth into position to engage the work and hold the arm out of engagement with the controlling means until the work has reached the required size and then to clear the work and permit the arm to actuate said means, thereby stopping the feed motion of the machine tool.

2. The combination in an apparatus for cutting off the feed motion of a machine tool when the work has reached its predetermined size, of controlling means therefor, and a pivoted trip lever adapted to actuate said controlling means and having a movable'part with a plurality of work-engaging arms of different radial length, said part movable to bring any of such arms to position to contact with .the work, whereby to hold the trip lever out of action until the work is reduced to a dimension determined by the length of the contacting arm.

NILS JOSEF OLSSON.

In testimony whereof I affix my signature. 

